JPH05230343A - Lubricating medium-impregnated molding - Google Patents

Abstract

PURPOSE:To provide the subject molded product not injuring other members, excellent in the abrasion resistance and heat resistance, and useful for high speed sliding members under high loads, etc., by impregnating the molding of a specific thermotropic liquid crystal polymer with a lubricating medium. CONSTITUTION:(A) The molded product of a thermotropic liquid crystal polymer comprising a polymer or copolymer containing monomer units of the formula is impregnated with (B) a lubricating medium such as a silicone oil preferably in an amount of >=0.03wt.% under a pressure of 100-3000kgf/cm<2> to provide the objective molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating medium-impregnated molded product which can be used in sliding parts in high load and high speed regions.

[0002]

2. Description of the Related Art As a resin composition having excellent slidability,
Resins such as polyamide, polyacetal, polyphenylene sulfide, and polytetrafluoroethylene added with additives such as solid lubricants and lubricating oils for improving sliding characteristics have been used. These can be used without any problems in the relatively low load and low speed regions, but cannot be used in the high load and high speed regions because they are easily worn and cause seizure or melting due to frictional heat. Therefore, for the purpose of improving wear resistance and heat resistance, glass fibers, carbon fibers, various whiskers, etc. are added, but these fillers have a point of abrading the metal or resin of the partner used in the sliding portion. It becomes a problem.

As a sliding material which can be used in a high load and high speed range, Japanese Patent Application No. 2-105273 discloses a sliding resin composition comprising a thermotropic liquid crystal polymer, glassy carbon and graphite. Is disclosed. However, the characteristics of this resin composition are obtained only by using a specific inorganic filler in a specific mixing range. Further, Japanese Patent Laid-Open No. 63-297453 discloses that
A resin composition is disclosed in which two types of lubricating oils having specific viscosities are blended with a thermoplastic polyester resin and melt-kneaded. However, for example, a resin having a high melting point of 300 ° C. or higher poses a problem because the lubricating oil may be decomposed during melt kneading. The decomposed oil may adversely affect not only the mechanical properties of the obtained molded product but also the sliding properties. Further, since the polymer has a high viscosity, it is difficult to mix a low-viscosity liquid, and it is difficult to obtain a uniform composition.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lubricating medium-impregnated molded article which is excellent in abrasion resistance, does not damage the mating material, and has excellent heat resistance without adding a specific inorganic filler. To provide.

[0005]

The present invention provides a molded article of a thermotropic liquid crystal polymer comprising a polymer or a copolymer containing a monomer unit represented by the following general formula 2,
The present invention relates to a lubrication medium-impregnated molded article, which is impregnated with a lubrication medium.

[Chemical 2]

The present invention will be described in detail below. The thermotropic liquid crystal polymer in the present invention is a polymer which exhibits optical anisotropy when melted and has thermoplasticity.
As described above, the polymer exhibiting optical anisotropy when melted has a property that the polymer molecular chains have a regular parallel arrangement in the melted state. The properties of the optically anisotropic molten phase can be confirmed by a usual polarization inspection method using a crossed polarizer.
Examples of the above-mentioned liquid crystal polymer include liquid crystal polyester, liquid crystal polycarbonate, liquid crystal polyester imide and the like, and specifically (all) aromatic polyester, polyester amide, polyamide imide, polyester carbonate, polyazomethine and the like. Thermotropic liquid crystal polymers generally have an elongated, flat molecular structure, have high rigidity along the long chain of the molecule, and have a plurality of chain extension bonds in either a coaxial or parallel relationship. In the thermotropic liquid crystal polymer used in the present invention, a part of one polymer chain is composed of a polymer segment forming an anisotropic melt phase, and the remaining part is a polymer segment not forming an anisotropic melt phase. Polymers composed of are also included. Further, it also includes a composite of a plurality of thermotropic liquid crystal polymers.

Typical examples of the monomer constituting the thermotropic liquid crystal polymer include (A) at least one aromatic dicarboxylic acid, (B) at least one aromatic hydroxycarboxylic acid compound, and (C) aromatic diol. At least one compound, (D) (D1) aromatic dithiol, (D2) aromatic thiophenol, (D3) at least one aromatic thiol carboxylic acid compound, (E) aromatic hydroxyamine, aromatic diamine system Aromatic compounds such as at least one compound. These may be used alone, but in most cases (A) and (C);
(A) and (D); (A), (B) and (C); (A),
(B) and (E); or (A), (B), (C) and (E), and the like.

Examples of the aromatic dicarboxylic acid compound (A) include terephthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid and 1,4- Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenoxyethane-
4,4'-dicarboxylic acid, diphenoxybutane-4,4'-
Dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenylether-3,3'-dicarboxylic acid, diphenoxyethane-3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, 1,6
An aromatic dicarboxylic acid such as naphthalene dicarboxylic acid,
Or chloroterephthalic acid, dichloroterephthalic acid,
Examples thereof include alkyl, alkoxy or halogen substitution products of the above aromatic dicarboxylic acids represented by bromoterephthalic acid, methyl terephthalic acid, dimethyl terephthalic acid, ethyl terephthalic acid, methoxy terephthalic acid, ethoxy terephthalic acid and the like.

(B) Aromatic hydroxycarboxylic acid compounds include aromatic hydroxy such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and 6-hydroxy-1-naphthoic acid. Carboxylic acid or 3-methyl-4-hydroxybenzoic acid, 3,
5-Dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-
Hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5-methyl-2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid, 2-chloro-4-hydroxybenzoic acid Acid, 3-chloro-4-hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3- Bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy-
7-chloro-2-naphthoic acid, 6-hydroxy-5,7
-Alkyl, alkoxy or halogen substitution products of aromatic hydroxycarboxylic acid such as dichloro-2-naphthoic acid.

As the (C) aromatic diol, 4,4'-
Dihydroxydiphenyl, 3,3'-dihydroxydiphenyl, 4,4'-dihydroxytriphenyl, hydroquinone, resorcin, 2,6-naphthalenediol,
4,4'-dihydroxydiphenyl ether, bis (4-
Hydroxyphenoxy) ethane, 3,3′-dihydroxydiphenyl ether, 1,6-naphthalenediol,
2,2-bis (4-hydroxyphenyl) propane, bis
Aromatic diol such as (4-hydroxyphenyl) methane,
Or chlorohydroquinone, methylhydroquinone,
Examples thereof include alkyl-, alkoxy- or halogen-substituted aromatic diols such as tert-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-chlororesorcin, and 4-methylresorcin.

Examples of the aromatic dithiol (D1) include benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, and 2,7-naphthalene-dithiol. Examples of (D2) aromatic thiophenol include 4-mercaptophenol, 3-mercaptophenol, and 6-mercaptophenol. Examples of the aromatic thiolcarboxylic acid (D3) include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid and 7-mercapto-2-naphthoic acid.

Examples of (E) aromatic hydroxyamine and aromatic diamine compounds include 4-aminophenol and N-
Methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine, N,
N'-dimethyl-1,4-phenylenediamine, 3-aminophenol, 3-methyl-4-aminophenol, 2
-Chloro-4-aminophenol, 4-amino-1-naphthol, 4-amino-4'-hydroxydiphenyl,
4-amino-4'-hydroxydiphenyl ether, 4
-Amino-4'-hydroxydiphenylmethane, 4-amino-4'-hydroxydiphenyl sulfide, 4,4 '
-Diaminophenyl sulfide (thiodianiline),
4,4'-diaminodiphenylsulfone, 2,5-diaminotoluene, 4,4'-ethylenedianiline, 4,4'-diaminodiphenoxyethane, 4,4'-diaminodiphenylmethane (methylenedianiline), 4, 4'-diamino diphenyl ether (oxydianiline) etc. are mentioned.

The thermotropic liquid crystal polymer used in the present invention can be produced from the above-mentioned monomers by various ester forming methods such as a melt acidolysis method and a slurry polymerization method. Among the thermotropic liquid crystal polymers obtained from these monomers, aromatic polyesters which are polymers or copolymers containing the monomer unit represented by the general formula 3 as an essential component are preferable.

[0014]

[Chemical 3]

A particularly preferred wholly aromatic polyester of the present invention is a polyester represented by Chemical Formula 4 having repeating units derived from three compounds of p-hydroxybenzoic acid, phthalic acid and biphenol, or p-
It is a polyester represented by Chemical formula 5, which has repeating units derived from two compounds of hydroxybenzoic acid and hydroxynaphthoic acid.

[0016]

[Chemical 4]

[Chemical 5]

The thermotropic liquid crystal polymer used in the present invention preferably has a melting point of 300 ° C. or higher.
The sliding surface of the sliding member in the high load and high speed region may reach a considerably high temperature, for example, 200 ° C. or higher. Therefore, it is preferable to use a thermotropic liquid crystal polymer having a high melting point capable of withstanding such a temperature.

Further, it is preferable to add an additive to the thermotropic liquid crystal polymer of the present invention. As the additives, inorganic fillers, organic fillers, stabilizers, antioxidants,
Examples include UV absorbers, pigments, dyes, modifiers, and the like. Among the additives, inorganic fillers and organic fillers are particularly important and are often used for improving processability and physical properties.

Examples of the inorganic filler include glass fiber, carbon fiber, graphite fiber, brass fiber, stainless fiber, steel fiber, silica fiber, alumina fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron. Fiber, inorganic fiber such as potassium titanate fiber, glassy carbon (for example, glassy carbon obtained by carbonizing a phenolic thermosetting resin), glass beads,
Glass flakes, glass powder, quartz powder, glass microballoons, graphite (for example, flake graphite), molybdenum disulfide, bronze powder, kaolin, talc, mica, clay, wollastonite, sericite, titanium oxide, antimony oxide, carbonic acid. Examples thereof include calcium, calcium silicate, calcium phosphate, calcium pyrophosphate, silica, alumina, aluminum hydroxide, calcium hydroxide, fluorinated graphite, potassium titanate, calcium sulfate, barium sulfate and the like. Among these, glassy carbon and graphite are particularly preferably used. Examples of the organic filler include organic fibers such as aromatic polyester fibers, aromatic polyimide fibers, and aromatic polyamide fibers. By using these, it becomes possible to improve the sliding performance by a synergistic effect with the lubricating medium.

Further, by adding an appropriately selected additive, it becomes easy to secure a sufficient impregnation amount of the lubricating medium. Although the reason is not clear, the surface of the thermotropic liquid crystal polymer becomes rough by blending the additive, and the lubricating medium is easily impregnated in the polymer, or through the interface between the thermotropic liquid crystal polymer and the additive. Since the lubrication medium is impregnated and the lubrication medium is easily retained, it is considered that the lubrication medium can be secured in an amount that can withstand long-term use as a sliding material. The mixing ratio of the additive is 200 parts by weight or less, preferably 150 parts by weight or less per 100 parts by weight of the thermotropic liquid crystal polymer.

In addition to the above additives, other resin or polymer substance may be added to the molded article of the present invention. Examples of these resins or polymer substances include polyolefin resins and fluororesins. Among these, a fluororesin is particularly preferably used as a resin capable of imparting slidability.

In order to produce the lubricating medium-impregnated molded article of the present invention, the thermotropic liquid crystal polymer is preferably molded together with an additive by an arbitrary method such as injection, compression, extrusion, etc., and the molded article is then subjected to the lubricating medium. It is dipped in and impregnated at room temperature or with heating, preferably under pressure. By applying pressure, it is possible to uniformly impregnate the lubricating medium in a short time, and to obtain a product exhibiting a stable friction coefficient even in a high load and high speed range. If you do not pressurize,
It takes a long time to impregnate the lubricating medium, and the impregnated state tends to be uneven and insufficient. As a result, there is a disadvantage that the friction coefficient becomes unstable especially when used for high load and high speed, which is not preferable. The pressure at the time of pressurization is not particularly limited as long as it can be impregnated with a sufficient amount of the lubricating medium, but it is usually preferably 3,000 kgf / cm ² or less. More preferably, it is in the range of 100 to 3,000 kgf / cm ² . Three,
When it exceeds 000 kgf / cm ² , the cost of the pressurizing equipment increases, but the impregnation amount does not increase so much. The time required for pressurization varies depending on the pressure etc., but normally 5 minutes to
The range is 12 hours.

The amount of the lubricating medium to be impregnated is 0.001% by weight or more, preferably 0.01% by weight or more, more preferably 0.03% by weight or more, based on the weight of the molded product before impregnation. is there. When the lubricating medium is impregnated with at least 0.001% by weight of the lubricating medium, the lubricating medium-impregnated molded article of the present invention exhibits good sliding characteristics. Normally, it is difficult to impregnate a molded body with a lubricating medium in an amount exceeding 0.5% by weight by impregnating the molded body, but if possible, it may be impregnated with more than this.

There is no particular limitation on the method of applying pressure to impregnate, and a known method can be used. For example, it is possible to impregnate a molded body and a lubricating medium into an autoclave, immerse the molded body in the lubricating medium, and pressurize the inside of the autoclave to a predetermined pressure for impregnation. On this occasion,
It is preferable that only the molded body is put into the autoclave in advance and the inside of the autoclave is evacuated, then the lubricating medium is introduced to bring the molded body and the lubricating medium into contact with each other, and the inside of the autoclave is pressurized to perform the impregnation operation. By doing so, the gas in the pores of the molded body is degassed in advance, so that the lubrication medium is more effectively impregnated.

The lubricating medium used in the present invention includes:
There is no particular limitation as long as it is a substance capable of imparting lubricity to the thermotropic liquid crystal polymer molded body, and a commercially available lubricating oil is used, but heat resistance particularly when used for high load and high speed. Higher is preferable. Also,
In terms of ease of impregnation operation, it is generally preferable that the viscosity is low, and paste-like or grease-like ones
It is not preferable because it is not easy to carry out sufficient impregnation.

Examples of the lubricating medium include synthetic oils, mineral oils, animal and vegetable oils and the like. Examples of synthetic oils include silicone oils, organic ester oils, phosphate ester oils, synthetic hydrocarbon oils, polyalkylene glycol oils, polyol ester oils, polyphenylene oils, diester oils, polyolefin oils, and mineral oils such as paraffin. There are lubricating oils containing hydrocarbons of system, aromatic and naphthenic type as main components, and examples thereof include engine oil, turbine oil, dynamo oil, machine oil, spindle oil, gear oil and the like. Examples of animal and vegetable oils include soybean oil, coconut oil, olive oil, palm oil, cottonseed oil, linseed oil, rapeseed oil, castor oil, cutting oil, squalene, squalane and the like. Of these, synthetic oils and mineral oils are preferably used.

Various additives usually used for lubricating oils can be added to the lubricating medium of the present invention. As the additives usually used, antioxidants, rust preventives, antiwear agents, detergent dispersants, pour point depressants, viscosity index improvers,
Examples include defoaming agents.

The lubricating medium-impregnated molded product of the present invention has excellent sliding properties and wear resistance, and therefore (1) rotating shafts of electric appliances, office machines, power equipment, etc .; bearings; various gears; cams. ;
End faces of mechanical seals, valve seats such as valves, seal members such as V rings, rod packings, piston rings, rider rings, etc. (2) Rotating shafts of compressors, rotating sleeves, pistons, impellers, rollers, etc. You can

[0029]

The present invention will be described in more detail with reference to Examples. These examples do not limit the scope of the invention, but represent preferred embodiments of the invention. First,
Raw materials used in Examples and Comparative Examples are collectively shown. (A) Thermotropic liquid crystal copolyester consisting of terephthalic acid, 4-hydroxybenzoic acid and 4,4'-dihydroxydiphenyl (molar ratio of the above components 1: 2:
1, melting point 420 ° C. by DSC), (B) spherical glassy carbon obtained by carbonizing a phenolic thermosetting resin, (C) scaly graphite A having an average particle size of 10 μm
CP (trade name, manufactured by Nippon Graphite Co., Ltd.).

<Examples 1 to 6> A disk having a diameter of 5 cm and a thickness of 3 mm was injection-molded by a conventional method from the thermotropic liquid crystal polymer composition obtained by mixing the above materials in the proportions shown in Table 1. .. Lubricating oil Super Highland 32 (trade name, Nippon Oil Co., Ltd.)
Was manufactured in an autoclave at a pressure of 2,000 kgf / cm ² at room temperature for 30 minutes. The molded body was taken out, the surface lubricating oil was washed off with acetone, and the weight of the molded body was measured. As a result, about 0.03 to 0.05 wt% of the weight of the molded product
A lubrication medium-impregnated molded article containing the lubrication medium of was obtained.
Using a Suzuki type friction and wear tester,
Ring-shaped S with an outer diameter of 25.6 mm and an inner diameter of 20 mm as the mating material
The wear coefficient, the friction coefficient, and the wear amount of the mating material were measured under the pressure, speed, and time conditions shown in Table 1 using 45C steel. The results are shown in Table 1.

[0031]

[Table 1]

<Comparative Examples 1 to 5> Friction was carried out in the same manner as in Examples except that a disk was molded in the same manner as in Examples 1 to 4 and 6 and the molded body was not impregnated with a lubricating medium. A wear test was performed. The results are shown in Table 2.

[0033]

[Table 2]

As described above, in Examples 1 to 6, the effect of impregnating the lubricating medium is exhibited, and in particular, it is excellent in terms of the amount of wear of the mating material and the coefficient of friction. On the other hand, in Comparative Examples 1 to 4, the amount of wear of the mating material is larger than that in Examples 1 to 4 in which the lubricating medium is impregnated. In Comparative Example 5, the wear coefficient and the friction coefficient are larger than those in Example 6.

[0035]

EFFECTS OF THE INVENTION The lubricating medium-impregnated molded article of the present invention has the following features and is therefore most suitable as a sliding material used in a high-load and high-speed sliding portion. (1) Since the thermotropic liquid crystal polymer having high heat resistance is used, it is unlikely to cause melting and seizing due to frictional heat. (2) Due to impregnation with a lubricating medium, such as lubricating oil,
It shows good sliding characteristics over a long time without lubrication. (3) Since it is impregnated with a lubricating medium, for example, lubricating oil, it is less worn, and less likely to damage an iron material such as steel, which is a mating material of the sliding portion, or other metal material. (4) Furthermore, since the friction coefficient is small and the generation of frictional heat is suppressed, it can be used in a high temperature atmosphere as compared with the case where the lubricating medium is not impregnated.

Claims (2)

[Claims] 1. A lubrication medium impregnation, wherein a lubrication medium is impregnated into a molded body of a thermotropic liquid crystal polymer composed of a polymer or a copolymer containing a monomer unit represented by the following general formula 1. Molded body. [Chemical 1] 2. The lubricating medium-impregnated molded article according to claim 1, wherein the lubricating medium is impregnated under a pressure of 100 to 3,000 kgf / cm ² .